A variety of businesses, particularly in the fast food industry, employ part-time delivery vehicles. Typically, a business of this type will provide a sign that can be mounted on a part-time delivery person's own vehicle and removed at the end of that person's shift for use during a subsequent next shift. Such signs are usually mounted on the window or roof of delivery vehicles. There is a need for a vehicle mounted sign assembly design that could increase the effectiveness and security of attachment of advertising signs to any type of vehicles.